Methods for producing peroxidic materials



United States Patent 3,160,667 METHGDS 1 9R lRGDUCiNG FERQXEDHCMATERIALS Kazuo Higashiuchi, Chicago, 151., and Edward 3. Schwoegler,Munster, 1nd, assignors to I. 1%.. Short *Tompany, Chicago, 12., acorporaticn of lllinnis No Drawing. Filed Dec. 14, 1960, Ser. No. 75,6925 Qlaims. (til. 26ti--6iil) This invention relates to organic peroxidesand more particularly to a method for producing compositions containingrelatively large proportions of the Water soluble compounds2,2-dihydroperoxy propane and bis-(1,1'-hydroperoxy 1,1-methyl) diethylperoxide, with the weight of the former equal to at least three timesthe weight of the latter.

As disclosed in copending application Serial Number 15,783, filed June23, 1959, on behalf of Herbert G. Renner, now US. Patent 3,085,014,issued April 9, 1963, acetone and aqueous hydrogen peroxide can bereacted under conditions such that, though the resulting reactionproduct mixture is at least substantially free from cyclic acetoneperoxides in solid form, the same contains a major proportion of acyclicperoxides in solution. Thus, a typical reaction product mixture preparedin accordance with application Serial Number 15,783 contains at least30% by weight, or more, of total organic peroxides, at most only anegligible proportion of which is made up by the cyclic dimeric andtrirneric acetone peroxides. Of this organic peroxide content, asubstantial proportion has been found to be bis-(1,1-hydroperoxy1,1'-methyl) diethyl peroxide, almost all of the remainder being 2,2-dihydroperoxy propane, if the reaction is properly carried out, and onlynegligible amounts of more highly polymeric acyclic acetone peroxidesbeing present.

As disclosed in application Serial Number 75,774, filed December 14,1960, by Kazuo Higashiuchi, now US. Patent 3,077,412, issued February12, 1963, 2,2-dihydroperoxy propane is superior, as a flour bleachingand maturing agent, to both bis-(1,l'-hydroperoxy l,l'-methyl) diethylperoxide and reaction mixtures containing the latter as the primaryorganic peroxide. Thus, a composition wherein the organic peroxidecontent consists essentially of 2,2-dihydroperoxy propane has a flourbleaching capability more than 33% greater than one wherein the organicperoxide content consists essentially of bis-(l,lhydroperoxy l,1-methyl)diethyl peroxide, and at least 33% greater than one containing both2,2-dihydroperoxy propane and bis-(l,1-hydroperoxy l,l'-methyl) diethylperoxide with a ratio of the former to the latter of, for example, 2:1.Despite the superior bleaching power of 2,2-dihydroperoxy propane, itmust be recognized that processing steps required for obtaining thatcompound in reasonably pure form are expensive, so that it is desirableto capitalize on the superior capabilities of 2,2-dihydroperoxy propanewithout undertaking isolation of that compound.

A general object of the present invention is to devise a method forreacting acetone and hydrogen peroxide in such manner as to obtain ahigh total organic peroxide yield consisting essentially of2,2-dihydroperoxy propane and bis-(l,l'-hydroperoxy l,1'-methyl) diethylperoxide with the weight of the former being at least three times thatof the latter. 7

Another object is to provide such a method capable of producing2,2-dihydroperoxy propane and bis-(l,l'-hy droperoxy l,l'-methyl)diethyl peroxide in weight ratios up to 10:1 and even higher, so that2,2-di'nydroperoxy propane is made the major peroxide of the reactionproduct mixture and special steps for recovering or concentrating thatcompound are avoided.

We have discovered that various specific conditions affecting thereaction of acetone and hydrogen peroxide act decidedly to promote theformation of 2,2-dihydroperoxy propane. First, and of especialimportance, we have discovered that phosphoric acid acts in some fashionto promote production of 2,2-dihydroperoxy propane at the expense offormation of bis-(1,1'-hydroperoxy 1,1- methyl) diethyl peroxide, andthat the use of this particular acid as the catalyst allows selection ofother reaction conditions, which favor production of 2,2-dihydroperoxypropane, without danger of material formation of cyclic trimeric acetoneperoxide. Next, we have found that the proportion of 2,2-dihydroperoxypropane in the reaction product mixture is increased by maintaining themolar ratio of hydrogen peroxide to acetone in the range of from 1.5 :1to 6:1, with best results being attained with the narower range of from2:1 to 3:1, and by employing water in an amount equal to 5-95 andadvantageously 35-55%, of the reaction mixture weight, reaction beingaccomplished by maintaining the reaction mixture at a temperature offrom 20 C. to 35 C..

and at a temperature of. from -l0 C. to +15 C. for.

best results, for a period of from 10 minutes to 6 hours, depending uponthe amount of catalyst and the temperature employed. As described insaid copending application Serial Number 75,774, the reaction timeincreases with a decrease in either temperature or the proportion ofcatalyst, and decreases when either the temperature or the proportion ofcatalyst is increased. When these specific process conditions areemployed, we have found that a yield of organic peroxide amounting, inhydrogen peroxide equivalents, to at least 60% of the hydrogen peroxidestarting material will be obtained, with the organic peroxide formedconsisting essentially of 2,2- dihydroperoxy propane andbis-(l,1'-hydroperoxy 1,1- methyl) diethyl peroxide in a weight ratio ofat least 3:1.

in considering the molar ratio given above for hydrogen peroxide toacetone, it must be recognized that the process is aided by gradualaddition of the acetone over at least a major portionof the reactiontime and that the molar ratio refers to all of the acetone employed. Inconsidering the proportion of water, the perwntages set out above arefor added water and do not take into account water produced by thereaction. Conveniently, all of the added water is provided by employingan aqueous hydrogen peroxide solution of the proper concentration.

The following example illustrates the marked superiority of phosphoricacid as a catalyst when high proportions of 2,2-dihydroperoxy propaneare to be produced.

Example 1 In each of runs lA-lF, tabulated below, acetone and aqueoushydrogen peroxide were combined to provide a molar ratio of hydrogenperoxide to acetone of 2.0, and

reaction was accomplished by maintaining the reaction mixtures at 15 C.for the time periods indicated.

Catalyst Ratio of 2,2-dihy- Time droperoxy propane to Run (hours)bis-(1,1-hydroperoxy Acid Per- 1,1-methyl) diethyl cent peroxide 6.15 12. 77 0. l5 2 2. t7 0. 15 1 3. 03 0. l5 2 2. 6 HaPO'4 0.15 1 '5. 2 133104-"- 0.15 2 4.3

While a 3:1 ratio of 2,2-dihydroperoxy propane to bis- (l,l'-hydroperoxyl,l-methyl) diethyl peroxide was obtained in run 1C, involving areaction time of 1 hour, this ratio fell sharply below the desired 3:1lower limit when the reaction time was extended to 2 hours. Hydrochloricacid is not included here because of its marked tendency to promote theformation of cyclic trimeric acetone peroxide. Thus, hydrochloric acidhas been found to cause production of the undesirable cyclic trimerabout times faster than does nitric acid and about times faster thandoes sulfuric acid.

Employing phosphoric acid as the catalyst, it has been found that thebest ratio of 2,2-dihydroperoxy propane to bis-(l,1'-hydroperoxy1,1'-methyl) diethyl peroxide is obtained when the catalyst is employedin an amount equal to 16% by weight, while the total yield of the twoperoxides can be increased, but at the expense of a decrease in therelative proportion of 2,2-dihydroperoxy propane, by increasing theamount of phosphoric acid above 6%. The following example isillustrative.

Example 2 For all of runs 2A-2C, tabulated below, and all catalyzed byphosphoric acid, hydrogen peroxide and acetone were employed in a molarratio of 2.5: 1, and reaction was accomplished by maintaining thereaction mixture at C. for 30 minutes, the acetone being added graduallyover the reaction period.

In general, lower reaction temperatures favor production of2,2-dihydroperoxy propane, as indicated by the following example.

Example 3 Runs 3A and 3B, tabulated below, were made separately. In eachrun, the molar ratio of hydrogen peroxide to acetone was 2.5 :1, theacetone being added over the entire reaction period. Both reactionmixtures were catalyzed by phosphoric acid at the rate of 12 g. acid permole of acetone. The reaction time was 30 minutes for each run.

Ratio of 2,2-dihydroperoxy propane to bis-(1,1-hydroperoxy 1,1-methyl)diethyl peroxide Temp. 0.)

The amount of water employed in the reaction mixture has been found tohave a marked efiFect on the relative proportion of 2,2 -dihydroperoxypropane, as illustrated by the following example.

Example 4 Runs 4A-4C, tabulated below, were each made with an initialreaction mixture containing 23.4 g. acetone, 34.1 g. hydrogen peroxide(100%), and 3 g. phosphoric acid per mole acetone, the water contentbeing as indicated below and reaction being accomplished by maintainingthe reaction mixtures at 15 C. for 30 minutes in each run.

Ratio of 2,2dihydro Water peroxy propane to Run (percentbis-(1,1-hyd1oper0xy by wt.) 1,1-methyl) diethyl peroxide The increasedproportion of 2,2-dihydroperoxy propane obtained by increasing theproportion of water is accompanied by a decrease in total yield oforganic peroxide and it is accordingly most advantageous to keep theproportion of water in the range of 35-55%.

As already indicated, higher proportions of hydrogen peroxide in theinitial reaction mixture promote formation of 2,2-hydroperoxy propane,and a molar ratio of at least 15:1 for hydrogen peroxide to acetone isemployed in accordance with the invention. Addition of the acetone overa major portion of the reaction period is also helpful in this regard,since gradual addition of the acetone provides a higher ratio ofhydrogen peroxide to acetone in the early stages of the reaction. Thephenomenon is illustrated by the following example.

Example 5 Ratio of 2,2-dlhydroperoxy propane to Run bis-(1,1-hydroperox1,1-methyl) diethyl peroxide What is claimed is:

1. The method for obtaining from acetone and hydrogen peroxide a yieldof organic acyclic peroxides consisting essentially of 2,2-dihydroperoxypropane and bis-(1,1- hydroperoxy 1,1'-methyl) diethyl peroxide andamounting in hydrogen peroxide equivalents to at least 60% of thehydrogen peroxide employed as a starting material,

with the weight ratio of 2,2-dihydroperoxy propane tobis-(1,l'-hydroperoxy 1,1'-methyl) diethyl peroxide being at least 3:1,comprising combining acetone, hydrogen peroxide, water and 0.15-15 byweight of phosphoric acid, and maintaining the resulting reactionmixture at a temperature of from 20 C. to 35 C. for a time period offrom 6 hours to 10 minutes, said time period depending uponand beinginversely related to the proportion of catalyst and the temperatureemployed, the molar ratio of hydrogen peroxide to acetone for the totalacetone employed being from 1.521 to 6:1, and the water employedamounting to 5-95% of the reaction mixture.

2. The method of claim 1 wherein the molar ratio of hydrogen peroxide toacetone is from 2:1 to 3:1.

3. The method of claim 2 wherein the reaction mixture is maintained at atemperature of from 10 C. to 15 C. and the proportion of phosphoric acidemployed is 1.56% by weight.

4. The method of claim 1 wherein the water employed amounts to 35-55% byweight of the reaction mixture.

5. The method of claim 4 wherein the reaction mixture is maintained at atemperature of from 10 C. to 15 C. and the proportion of phosphoric acidemployed is 1.56% by weight.

References Cited by the Examiner UNITED STATES PATENTS 3,003,000 10/61Milas 260-610 3,085,014 4/63 Renner 260610 X OTHER REFERENCES Criegee etal.: Ber. deut. chem., 89217144718 (5 pages) (1956).

LEON ZITVER, Primary Examiner.

CHARLES B. PARKER, Examiner.

1. THE METHOD FOR OBTAINING FROM ACETONE AND HYDROGEN PEROXIDE A YIELDOF ORGANIC ACYCLIC PEROXIDES CONSISTING ESSENTIALLY OF 2,2-DIHYDROPEROXYPROPANE AND BIS-(1,1''HYDROPEROXY, 1,1''-METHYL) DIETHYL PEROXIDE ANDAMOUNTING IN HYDROGEN PEROXIDE EQUIVALENTS TO AT LEAST 60% OF THEHYDROGEN PEROXIDE EMPLOYED AS A STARTING MATERIAL, WITH THE WEIGHT RATIOOF 2,2-DIHYDROPEROXY PROPANE TO BIS-(1,1''-HYDROPEROXY, 1,1''-METHYL)DIETHYL PEROXIDE BEING AT LEAST 3:1, COMPRISING COMBINING ACETONE,HYDROGEN PEROXIDE, WATER AND 0.15-15% BY WEIGHT OF PHOSPHORIC ACID, ANDMAINTAINING THE RESULTING REACTION MIXTURE AT AT TEMPERATURE OF FROM-20*C. TO 35*C. FOR A TIME PERIOD OF FROM 6 HOURS TO 10 MINUTES, SAIDTIME PERIOD DEPENDING UPON AND BEING INVERSELY RELATED TO THE PROPORTIONOF CATALYST AND THE TEMPERATURE EMPLOYED, THE MOLAR RATIO OF HYDROGENPEROXIDE TO ACETONE FOR THE TOTAL ACETONE EMPLOYED BEING FROM 1.5:1 TO6:1, AND THE WATER EMPLOYED AMOUNTING TO 5-95% OF THE REACTION MIXTURE.